Oil mist separation mechanism of internal combustion engine

Abstract

An oil mist separation mechanism of an internal combustion engine includes an oil mist separation portion being integrally provided with an internal combustion engine main body at an outer surface thereof, the oil mist separation portion for separating an oil mist included in a blow-by gas sent from the internal combustion engine main body, and an oil returning portion being connected to the oil mist separation portion, the oil returning portion returning an oil separated by the oil mist separation portion to an oil stored at a lower portion of the internal combustion engine main body.

The invention claimed is: 
     
       1. An oil mist separation mechanism of an internal combustion engine, comprising:
 an oil mist separation portion being integrally provided with an internal combustion engine main body at an outer surface thereof, the oil mist separation portion for separating an oil mist included in a blow-by gas sent from the internal combustion engine main body, the oil mist separation portion having a first side, a second side opposite the first side, and a bottom surface portion inclined downwardly toward the second side from the first side; and 
 an oil returning portion being connected to the oil mist separation portion, the oil returning portion returning an oil separated by the oil mist separation portion to an oil stored at a lower portion of the internal combustion engine main body, wherein 
 the oil mist separation portion is provided with a turning structure including a first blow-by gas passage portion sending the blow-by gas in a first direction toward the second side from the first side, and a second blow-by gas passage portion being connected to the first blow-by gas passage portion and sending the blow-by gas in a second direction that is opposite to the first direction; and 
 the first blow-by gas passage portion includes an inlet of the blow-by gas disposed at an end portion of an upstream in a flow direction of the blow-by gas, and the second blow-by gas passage portion includes an outlet of the blow-by gas disposed at an end portion of a downstream in the flow direction of the blow-by gas. 
 
     
     
       2. The oil mist separation mechanism of the internal combustion engine according to  claim 1 , wherein:
 the oil mist separation portion includes an oil returning hole being connected to the oil returning portion and is integrally provided with the internal combustion engine main body at an upper surface of the outer surface of the internal combustion engine main body; and 
 the oil returning portion includes an oil returning passage having an upper end portion that is connected to the oil returning hole, the oil returning passage extending downwardly and linearly from the oil returning hole. 
 
     
     
       3. The oil mist separation mechanism of the internal combustion engine according to  claim 1 , wherein:
 the oil mist separation portion includes an oil returning hole being connected to the oil returning portion and being provided between the first blow-by gas passage portion and the second blow-by gas passage portion; and 
 the bottom surface portion is inclined downwardly towards the oil returning hole. 
 
     
     
       4. The oil mist separation mechanism of the internal combustion engine according to  claim 1  wherein
 the internal combustion engine main body is configured such that a sliding direction of a piston is along with a horizontal direction; and 
 the oil mist separation portion includes: 
 a blow-by gas inlet opening downwardly; and 
 a partition wall being provided so as to separate a crankshaft and the blow-by gas inlet of the internal combustion engine main body from each other. 
 
     
     
       5. The oil mist separation mechanism of the internal combustion engine according to  claim 1 , wherein the oil mist separation portion includes an oil returning hole being provided in the bottom surface portion of the oil mist separation portion and being connected to the oil returning portion. 
     
     
       6. The oil mist separation mechanism of the internal combustion engine according to  claim 5 , wherein
 the oil returning portion includes an upper end portion that is connected to the oil returning hole and a lower end portion that is soaked in the oil; and 
 the oil returning portion includes a diameter of a passage in which an oil is not sucked up by manifold vacuum. 
 
     
     
       7. The oil mist separation mechanism of the internal combustion engine according to  claim 1 , wherein at least one of the first blow-by gas passage portion and the second blow-by gas passage portion includes a labyrinth structure. 
     
     
       8. The oil mist separation mechanism of the internal combustion engine according to  claim 1 , wherein the internal combustion engine main body is a stationary type or a movable type.